Numerous Jets Spied with New Sky Survey

byShannon HallonJuly 31, 2014

The area shown here was part of the very first image taken for the UWISH2 survey. Near the top is a region of massive star formation (called G35.2N) with two spectacular jets. Near the bottom is an intermediate mass young stellar cluster (Mercer14). Several jets are visible in its vicinity, as well as a region of photo-ionized material surrounding a young massive star. Image Credit: University of Kent

Jets — narrow beams of matter spat out at a high speed — typically accompany the most enigmatic astronomical objects. We see them wherever gas accretes onto compact objects, such as newborn stars or black holes. But never before have astronomers detected so many at once.

This remarkable discovery is expected to prompt significant changes in our understanding of the planetary nebulae population in the Galaxy, as well as properties of jets ejected from young forming stars.

The results come from a five-year survey (officially dubbed UWISH2) covering approximately 180 degrees of the northern sky, or 1450 times the size of the full moon. The survey utilizes the 3.8-meter UK Infrared Telescope on Mauna Kea, Hawai’i.

This image shows a field that contains a newly discovered photogenic planetary nebulae, known as “Jelly-Fish PN.” It shows an almost circular ring of emission from molecular hydrogen with a variety of structure in the ring itself and inside. Image Credit: University of Kent

At these longer wavelengths, any cosmic dust becomes transparent, allowing us to see regions previously hidden from view. This includes jets from protostars and planetary nebulae, as well as supernova remnants, the illuminated edges of vast clouds of gas and dust, and the warm regions that envelope massive stars and their associated clusters of smaller stars.

Based on current estimates using these data, the project expects to identify about 1000 jets from young stars — at least 90 percent of which are new discoveries — as well as 300 planetary nebulae — at least 50 percent of which are also new.

“These discoveries are very exciting,” said lead author Dirk Froebrich from the University of Kent in a press release. “We will ultimately have much better statistics, meaning we will be able to investigate the physical mechanisms that determine the jet lengths, as well as their power. This will bring us much closer to answering some of the fundamental questions of star formation: How are these jets launched and how much energy, mass and momentum do they feed back into the surrounding interstellar medium.”

Shannon Hall is a freelance science journalist. She holds two B.A.'s from Whitman College in physics-astronomy and philosophy, and an M.S. in astronomy from the University of Wyoming. Currently, she is working toward a second M.S. from NYU's Science, Health and Environmental Reporting program. You can follow her on Twitter @ShannonWHall.